1001 lines
34 KiB
Java
1001 lines
34 KiB
Java
/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.util;
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import android.annotation.Nullable;
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import android.annotation.TestApi;
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import android.compat.annotation.UnsupportedAppUsage;
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import java.lang.reflect.Array;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.ConcurrentModificationException;
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import java.util.Iterator;
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import java.util.Map;
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import java.util.Set;
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import java.util.function.Consumer;
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import java.util.function.Predicate;
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/**
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* ArraySet is a generic set data structure that is designed to be more memory efficient than a
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* traditional {@link java.util.HashSet}. The design is very similar to
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* {@link ArrayMap}, with all of the caveats described there. This implementation is
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* separate from ArrayMap, however, so the Object array contains only one item for each
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* entry in the set (instead of a pair for a mapping).
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*
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* <p>Note that this implementation is not intended to be appropriate for data structures
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* that may contain large numbers of items. It is generally slower than a traditional
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* HashSet, since lookups require a binary search and adds and removes require inserting
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* and deleting entries in the array. For containers holding up to hundreds of items,
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* the performance difference is not significant, less than 50%.</p>
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*
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* <p>Because this container is intended to better balance memory use, unlike most other
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* standard Java containers it will shrink its array as items are removed from it. Currently
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* you have no control over this shrinking -- if you set a capacity and then remove an
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* item, it may reduce the capacity to better match the current size. In the future an
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* explicit call to set the capacity should turn off this aggressive shrinking behavior.</p>
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*
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* <p>This structure is <b>NOT</b> thread-safe.</p>
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*/
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@android.ravenwood.annotation.RavenwoodKeepWholeClass
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public final class ArraySet<E> implements Collection<E>, Set<E> {
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private static final boolean DEBUG = false;
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private static final String TAG = "ArraySet";
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/**
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* The minimum amount by which the capacity of a ArraySet will increase.
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* This is tuned to be relatively space-efficient.
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*/
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private static final int BASE_SIZE = 4;
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/**
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* Maximum number of entries to have in array caches.
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*/
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private static final int CACHE_SIZE = 10;
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/**
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* Caches of small array objects to avoid spamming garbage. The cache
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* Object[] variable is a pointer to a linked list of array objects.
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* The first entry in the array is a pointer to the next array in the
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* list; the second entry is a pointer to the int[] hash code array for it.
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*/
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static Object[] sBaseCache;
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static int sBaseCacheSize;
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static Object[] sTwiceBaseCache;
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static int sTwiceBaseCacheSize;
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/**
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* Separate locks for each cache since each can be accessed independently of the other without
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* risk of a deadlock.
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*/
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private static final Object sBaseCacheLock = new Object();
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private static final Object sTwiceBaseCacheLock = new Object();
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private final boolean mIdentityHashCode;
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@UnsupportedAppUsage(maxTargetSdk = 28) // Hashes are an implementation detail. Use public API.
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int[] mHashes;
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@UnsupportedAppUsage(maxTargetSdk = 28) // Storage is an implementation detail. Use public API.
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Object[] mArray;
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@UnsupportedAppUsage(maxTargetSdk = 28) // Use size()
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int mSize;
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private MapCollections<E, E> mCollections;
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private int binarySearch(int[] hashes, int hash) {
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try {
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return ContainerHelpers.binarySearch(hashes, mSize, hash);
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} catch (ArrayIndexOutOfBoundsException e) {
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throw new ConcurrentModificationException();
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}
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}
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@UnsupportedAppUsage(maxTargetSdk = 28) // Hashes are an implementation detail. Use indexOfKey(Object).
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private int indexOf(Object key, int hash) {
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final int N = mSize;
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// Important fast case: if nothing is in here, nothing to look for.
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if (N == 0) {
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return ~0;
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}
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int index = binarySearch(mHashes, hash);
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// If the hash code wasn't found, then we have no entry for this key.
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if (index < 0) {
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return index;
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}
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// If the key at the returned index matches, that's what we want.
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if (key.equals(mArray[index])) {
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return index;
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}
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// Search for a matching key after the index.
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int end;
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for (end = index + 1; end < N && mHashes[end] == hash; end++) {
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if (key.equals(mArray[end])) return end;
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}
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// Search for a matching key before the index.
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for (int i = index - 1; i >= 0 && mHashes[i] == hash; i--) {
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if (key.equals(mArray[i])) return i;
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}
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// Key not found -- return negative value indicating where a
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// new entry for this key should go. We use the end of the
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// hash chain to reduce the number of array entries that will
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// need to be copied when inserting.
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return ~end;
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}
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@UnsupportedAppUsage(maxTargetSdk = 28) // Use indexOf(null)
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private int indexOfNull() {
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final int N = mSize;
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// Important fast case: if nothing is in here, nothing to look for.
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if (N == 0) {
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return ~0;
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}
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int index = binarySearch(mHashes, 0);
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// If the hash code wasn't found, then we have no entry for this key.
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if (index < 0) {
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return index;
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}
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// If the key at the returned index matches, that's what we want.
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if (null == mArray[index]) {
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return index;
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}
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// Search for a matching key after the index.
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int end;
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for (end = index + 1; end < N && mHashes[end] == 0; end++) {
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if (null == mArray[end]) return end;
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}
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// Search for a matching key before the index.
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for (int i = index - 1; i >= 0 && mHashes[i] == 0; i--) {
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if (null == mArray[i]) return i;
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}
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// Key not found -- return negative value indicating where a
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// new entry for this key should go. We use the end of the
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// hash chain to reduce the number of array entries that will
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// need to be copied when inserting.
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return ~end;
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}
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@UnsupportedAppUsage(maxTargetSdk = 28) // Allocations are an implementation detail.
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private void allocArrays(final int size) {
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if (size == (BASE_SIZE * 2)) {
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synchronized (sTwiceBaseCacheLock) {
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if (sTwiceBaseCache != null) {
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final Object[] array = sTwiceBaseCache;
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try {
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mArray = array;
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sTwiceBaseCache = (Object[]) array[0];
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mHashes = (int[]) array[1];
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if (mHashes != null) {
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array[0] = array[1] = null;
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sTwiceBaseCacheSize--;
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if (DEBUG) {
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Log.d(TAG, "Retrieving 2x cache " + Arrays.toString(mHashes)
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+ " now have " + sTwiceBaseCacheSize + " entries");
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}
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return;
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}
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} catch (ClassCastException e) {
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}
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// Whoops! Someone trampled the array (probably due to not protecting
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// their access with a lock). Our cache is corrupt; report and give up.
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Slog.wtf(TAG, "Found corrupt ArraySet cache: [0]=" + array[0]
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+ " [1]=" + array[1]);
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sTwiceBaseCache = null;
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sTwiceBaseCacheSize = 0;
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}
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}
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} else if (size == BASE_SIZE) {
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synchronized (sBaseCacheLock) {
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if (sBaseCache != null) {
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final Object[] array = sBaseCache;
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try {
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mArray = array;
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sBaseCache = (Object[]) array[0];
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mHashes = (int[]) array[1];
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if (mHashes != null) {
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array[0] = array[1] = null;
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sBaseCacheSize--;
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if (DEBUG) {
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Log.d(TAG, "Retrieving 1x cache " + Arrays.toString(mHashes)
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+ " now have " + sBaseCacheSize + " entries");
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}
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return;
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}
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} catch (ClassCastException e) {
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}
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// Whoops! Someone trampled the array (probably due to not protecting
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// their access with a lock). Our cache is corrupt; report and give up.
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Slog.wtf(TAG, "Found corrupt ArraySet cache: [0]=" + array[0]
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+ " [1]=" + array[1]);
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sBaseCache = null;
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sBaseCacheSize = 0;
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}
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}
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}
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mHashes = new int[size];
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mArray = new Object[size];
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}
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/**
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* Make sure <b>NOT</b> to call this method with arrays that can still be modified. In other
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* words, don't pass mHashes or mArray in directly.
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*/
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@UnsupportedAppUsage(maxTargetSdk = 28) // Allocations are an implementation detail.
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private static void freeArrays(final int[] hashes, final Object[] array, final int size) {
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if (hashes.length == (BASE_SIZE * 2)) {
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synchronized (sTwiceBaseCacheLock) {
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if (sTwiceBaseCacheSize < CACHE_SIZE) {
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array[0] = sTwiceBaseCache;
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array[1] = hashes;
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for (int i = size - 1; i >= 2; i--) {
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array[i] = null;
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}
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sTwiceBaseCache = array;
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sTwiceBaseCacheSize++;
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if (DEBUG) {
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Log.d(TAG, "Storing 2x cache " + Arrays.toString(array) + " now have "
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+ sTwiceBaseCacheSize + " entries");
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}
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}
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}
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} else if (hashes.length == BASE_SIZE) {
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synchronized (sBaseCacheLock) {
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if (sBaseCacheSize < CACHE_SIZE) {
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array[0] = sBaseCache;
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array[1] = hashes;
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for (int i = size - 1; i >= 2; i--) {
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array[i] = null;
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}
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sBaseCache = array;
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sBaseCacheSize++;
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if (DEBUG) {
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Log.d(TAG, "Storing 1x cache " + Arrays.toString(array) + " now have "
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+ sBaseCacheSize + " entries");
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}
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}
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}
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}
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}
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/**
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* Create a new empty ArraySet. The default capacity of an array map is 0, and
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* will grow once items are added to it.
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*/
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public ArraySet() {
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this(0, false);
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}
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/**
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* Create a new ArraySet with a given initial capacity.
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*/
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public ArraySet(int capacity) {
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this(capacity, false);
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}
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/** {@hide} */
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public ArraySet(int capacity, boolean identityHashCode) {
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mIdentityHashCode = identityHashCode;
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if (capacity == 0) {
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mHashes = EmptyArray.INT;
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mArray = EmptyArray.OBJECT;
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} else {
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allocArrays(capacity);
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}
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mSize = 0;
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}
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/**
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* Create a new ArraySet with the mappings from the given ArraySet.
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*/
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public ArraySet(ArraySet<E> set) {
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this();
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if (set != null) {
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addAll(set);
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}
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}
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/**
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* Create a new ArraySet with items from the given collection.
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*/
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public ArraySet(Collection<? extends E> set) {
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this();
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if (set != null) {
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addAll(set);
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}
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}
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/**
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* Create a new ArraySet with items from the given array
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*/
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public ArraySet(@Nullable E[] array) {
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this();
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if (array != null) {
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for (E value : array) {
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add(value);
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}
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}
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}
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/**
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* Make the array map empty. All storage is released.
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*/
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@Override
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public void clear() {
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if (mSize != 0) {
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final int[] ohashes = mHashes;
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final Object[] oarray = mArray;
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final int osize = mSize;
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mHashes = EmptyArray.INT;
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mArray = EmptyArray.OBJECT;
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mSize = 0;
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freeArrays(ohashes, oarray, osize);
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}
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if (mSize != 0) {
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throw new ConcurrentModificationException();
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}
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}
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/**
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* Ensure the array map can hold at least <var>minimumCapacity</var>
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* items.
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*/
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public void ensureCapacity(int minimumCapacity) {
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final int oSize = mSize;
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if (mHashes.length < minimumCapacity) {
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final int[] ohashes = mHashes;
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final Object[] oarray = mArray;
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allocArrays(minimumCapacity);
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if (mSize > 0) {
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System.arraycopy(ohashes, 0, mHashes, 0, mSize);
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System.arraycopy(oarray, 0, mArray, 0, mSize);
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}
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freeArrays(ohashes, oarray, mSize);
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}
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if (mSize != oSize) {
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throw new ConcurrentModificationException();
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}
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}
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/**
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* Check whether a value exists in the set.
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*
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* @param key The value to search for.
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* @return Returns true if the value exists, else false.
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*/
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@Override
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public boolean contains(Object key) {
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return indexOf(key) >= 0;
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}
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/**
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* Returns the index of a value in the set.
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*
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* @param key The value to search for.
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* @return Returns the index of the value if it exists, else a negative integer.
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*/
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public int indexOf(Object key) {
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return key == null ? indexOfNull()
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: indexOf(key, mIdentityHashCode ? System.identityHashCode(key) : key.hashCode());
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}
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/**
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* Return the value at the given index in the array.
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*
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* <p>For indices outside of the range <code>0...size()-1</code>, the behavior is undefined for
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* apps targeting {@link android.os.Build.VERSION_CODES#P} and earlier, and an
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* {@link ArrayIndexOutOfBoundsException} is thrown for apps targeting
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* {@link android.os.Build.VERSION_CODES#Q} and later.</p>
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*
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* @param index The desired index, must be between 0 and {@link #size()}-1.
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* @return Returns the value stored at the given index.
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*/
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public E valueAt(int index) {
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if (index >= mSize && UtilConfig.sThrowExceptionForUpperArrayOutOfBounds) {
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// The array might be slightly bigger than mSize, in which case, indexing won't fail.
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// Check if exception should be thrown outside of the critical path.
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throw new ArrayIndexOutOfBoundsException(index);
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}
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return valueAtUnchecked(index);
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}
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/**
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* Returns the value at the given index in the array without checking that the index is within
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* bounds. This allows testing values at the end of the internal array, outside of the
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* [0, mSize) bounds.
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*
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* @hide
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*/
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@TestApi
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public E valueAtUnchecked(int index) {
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return (E) mArray[index];
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}
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/**
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* Return true if the array map contains no items.
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*/
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@Override
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public boolean isEmpty() {
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return mSize <= 0;
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}
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/**
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* Adds the specified object to this set. The set is not modified if it
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* already contains the object.
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*
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* @param value the object to add.
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* @return {@code true} if this set is modified, {@code false} otherwise.
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*/
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@Override
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public boolean add(E value) {
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final int oSize = mSize;
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final int hash;
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int index;
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if (value == null) {
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hash = 0;
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index = indexOfNull();
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} else {
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hash = mIdentityHashCode ? System.identityHashCode(value) : value.hashCode();
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index = indexOf(value, hash);
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}
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if (index >= 0) {
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return false;
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}
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index = ~index;
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if (oSize >= mHashes.length) {
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final int n = oSize >= (BASE_SIZE * 2) ? (oSize + (oSize >> 1))
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: (oSize >= BASE_SIZE ? (BASE_SIZE * 2) : BASE_SIZE);
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if (DEBUG) Log.d(TAG, "add: grow from " + mHashes.length + " to " + n);
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final int[] ohashes = mHashes;
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final Object[] oarray = mArray;
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allocArrays(n);
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if (oSize != mSize) {
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throw new ConcurrentModificationException();
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}
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if (mHashes.length > 0) {
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if (DEBUG) Log.d(TAG, "add: copy 0-" + oSize + " to 0");
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System.arraycopy(ohashes, 0, mHashes, 0, ohashes.length);
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System.arraycopy(oarray, 0, mArray, 0, oarray.length);
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}
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freeArrays(ohashes, oarray, oSize);
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}
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if (index < oSize) {
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if (DEBUG) {
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Log.d(TAG, "add: move " + index + "-" + (oSize - index) + " to " + (index + 1));
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}
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System.arraycopy(mHashes, index, mHashes, index + 1, oSize - index);
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System.arraycopy(mArray, index, mArray, index + 1, oSize - index);
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}
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if (oSize != mSize || index >= mHashes.length) {
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throw new ConcurrentModificationException();
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}
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mHashes[index] = hash;
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mArray[index] = value;
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mSize++;
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return true;
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}
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/**
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* Special fast path for appending items to the end of the array without validation.
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* The array must already be large enough to contain the item.
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* @hide
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*/
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public void append(E value) {
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final int oSize = mSize;
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final int index = mSize;
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final int hash = value == null ? 0
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: (mIdentityHashCode ? System.identityHashCode(value) : value.hashCode());
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if (index >= mHashes.length) {
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throw new IllegalStateException("Array is full");
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}
|
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if (index > 0 && mHashes[index - 1] > hash) {
|
|
// Cannot optimize since it would break the sorted order - fallback to add()
|
|
if (DEBUG) {
|
|
RuntimeException e = new RuntimeException("here");
|
|
e.fillInStackTrace();
|
|
Log.w(TAG, "New hash " + hash
|
|
+ " is before end of array hash " + mHashes[index - 1]
|
|
+ " at index " + index, e);
|
|
}
|
|
add(value);
|
|
return;
|
|
}
|
|
|
|
if (oSize != mSize) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
|
|
mSize = index + 1;
|
|
mHashes[index] = hash;
|
|
mArray[index] = value;
|
|
}
|
|
|
|
/**
|
|
* Perform a {@link #add(Object)} of all values in <var>array</var>
|
|
* @param array The array whose contents are to be retrieved.
|
|
*/
|
|
public void addAll(ArraySet<? extends E> array) {
|
|
final int N = array.mSize;
|
|
ensureCapacity(mSize + N);
|
|
if (mSize == 0) {
|
|
if (N > 0) {
|
|
System.arraycopy(array.mHashes, 0, mHashes, 0, N);
|
|
System.arraycopy(array.mArray, 0, mArray, 0, N);
|
|
if (0 != mSize) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
mSize = N;
|
|
}
|
|
} else {
|
|
for (int i = 0; i < N; i++) {
|
|
add(array.valueAt(i));
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Removes the specified object from this set.
|
|
*
|
|
* @param object the object to remove.
|
|
* @return {@code true} if this set was modified, {@code false} otherwise.
|
|
*/
|
|
@Override
|
|
public boolean remove(Object object) {
|
|
final int index = indexOf(object);
|
|
if (index >= 0) {
|
|
removeAt(index);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/** Returns true if the array size should be decreased. */
|
|
private boolean shouldShrink() {
|
|
return mHashes.length > (BASE_SIZE * 2) && mSize < mHashes.length / 3;
|
|
}
|
|
|
|
/**
|
|
* Returns the new size the array should have. Is only valid if {@link #shouldShrink} returns
|
|
* true.
|
|
*/
|
|
private int getNewShrunkenSize() {
|
|
// We don't allow it to shrink smaller than (BASE_SIZE*2) to avoid flapping between that
|
|
// and BASE_SIZE.
|
|
return mSize > (BASE_SIZE * 2) ? (mSize + (mSize >> 1)) : (BASE_SIZE * 2);
|
|
}
|
|
|
|
/**
|
|
* Remove the key/value mapping at the given index.
|
|
*
|
|
* <p>For indices outside of the range <code>0...size()-1</code>, the behavior is undefined for
|
|
* apps targeting {@link android.os.Build.VERSION_CODES#P} and earlier, and an
|
|
* {@link ArrayIndexOutOfBoundsException} is thrown for apps targeting
|
|
* {@link android.os.Build.VERSION_CODES#Q} and later.</p>
|
|
*
|
|
* @param index The desired index, must be between 0 and {@link #size()}-1.
|
|
* @return Returns the value that was stored at this index.
|
|
*/
|
|
public E removeAt(int index) {
|
|
if (index >= mSize && UtilConfig.sThrowExceptionForUpperArrayOutOfBounds) {
|
|
// The array might be slightly bigger than mSize, in which case, indexing won't fail.
|
|
// Check if exception should be thrown outside of the critical path.
|
|
throw new ArrayIndexOutOfBoundsException(index);
|
|
}
|
|
final int oSize = mSize;
|
|
final Object old = mArray[index];
|
|
if (oSize <= 1) {
|
|
// Now empty.
|
|
if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to 0");
|
|
clear();
|
|
} else {
|
|
final int nSize = oSize - 1;
|
|
if (shouldShrink()) {
|
|
// Shrunk enough to reduce size of arrays.
|
|
final int n = getNewShrunkenSize();
|
|
|
|
if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to " + n);
|
|
|
|
final int[] ohashes = mHashes;
|
|
final Object[] oarray = mArray;
|
|
allocArrays(n);
|
|
|
|
if (index > 0) {
|
|
if (DEBUG) Log.d(TAG, "remove: copy from 0-" + index + " to 0");
|
|
System.arraycopy(ohashes, 0, mHashes, 0, index);
|
|
System.arraycopy(oarray, 0, mArray, 0, index);
|
|
}
|
|
if (index < nSize) {
|
|
if (DEBUG) {
|
|
Log.d(TAG, "remove: copy from " + (index + 1) + "-" + nSize
|
|
+ " to " + index);
|
|
}
|
|
System.arraycopy(ohashes, index + 1, mHashes, index, nSize - index);
|
|
System.arraycopy(oarray, index + 1, mArray, index, nSize - index);
|
|
}
|
|
} else {
|
|
if (index < nSize) {
|
|
if (DEBUG) {
|
|
Log.d(TAG, "remove: move " + (index + 1) + "-" + nSize + " to " + index);
|
|
}
|
|
System.arraycopy(mHashes, index + 1, mHashes, index, nSize - index);
|
|
System.arraycopy(mArray, index + 1, mArray, index, nSize - index);
|
|
}
|
|
mArray[nSize] = null;
|
|
}
|
|
if (oSize != mSize) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
mSize = nSize;
|
|
}
|
|
return (E) old;
|
|
}
|
|
|
|
/**
|
|
* Perform a {@link #remove(Object)} of all values in <var>array</var>
|
|
* @param array The array whose contents are to be removed.
|
|
*/
|
|
public boolean removeAll(ArraySet<? extends E> array) {
|
|
// TODO: If array is sufficiently large, a marking approach might be beneficial. In a first
|
|
// pass, use the property that the sets are sorted by hash to make this linear passes
|
|
// (except for hash collisions, which means worst case still n*m), then do one
|
|
// collection pass into a new array. This avoids binary searches and excessive memcpy.
|
|
final int N = array.mSize;
|
|
|
|
// Note: ArraySet does not make thread-safety guarantees. So instead of OR-ing together all
|
|
// the single results, compare size before and after.
|
|
final int originalSize = mSize;
|
|
for (int i = 0; i < N; i++) {
|
|
remove(array.valueAt(i));
|
|
}
|
|
return originalSize != mSize;
|
|
}
|
|
|
|
/**
|
|
* Removes all values that satisfy the predicate. This implementation avoids using the
|
|
* {@link #iterator()}.
|
|
*
|
|
* @param filter A predicate which returns true for elements to be removed
|
|
*/
|
|
@Override
|
|
public boolean removeIf(Predicate<? super E> filter) {
|
|
if (mSize == 0) {
|
|
return false;
|
|
}
|
|
|
|
// Intentionally not using removeAt() to avoid unnecessary intermediate resizing.
|
|
|
|
int replaceIndex = 0;
|
|
int numRemoved = 0;
|
|
for (int i = 0; i < mSize; ++i) {
|
|
if (filter.test((E) mArray[i])) {
|
|
numRemoved++;
|
|
} else {
|
|
if (replaceIndex != i) {
|
|
mArray[replaceIndex] = mArray[i];
|
|
mHashes[replaceIndex] = mHashes[i];
|
|
}
|
|
replaceIndex++;
|
|
}
|
|
}
|
|
|
|
if (numRemoved == 0) {
|
|
return false;
|
|
} else if (numRemoved == mSize) {
|
|
clear();
|
|
return true;
|
|
}
|
|
|
|
mSize -= numRemoved;
|
|
if (shouldShrink()) {
|
|
// Shrunk enough to reduce size of arrays.
|
|
final int n = getNewShrunkenSize();
|
|
final int[] ohashes = mHashes;
|
|
final Object[] oarray = mArray;
|
|
allocArrays(n);
|
|
|
|
System.arraycopy(ohashes, 0, mHashes, 0, mSize);
|
|
System.arraycopy(oarray, 0, mArray, 0, mSize);
|
|
} else {
|
|
// Null out values at the end of the array. Not doing it in the loop above to avoid
|
|
// writing twice to the same index or writing unnecessarily if the array would have been
|
|
// discarded anyway.
|
|
for (int i = mSize; i < mArray.length; ++i) {
|
|
mArray[i] = null;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Return the number of items in this array map.
|
|
*/
|
|
@Override
|
|
public int size() {
|
|
return mSize;
|
|
}
|
|
|
|
/**
|
|
* Performs the given action for all elements in the stored order. This implementation overrides
|
|
* the default implementation to avoid using the {@link #iterator()}.
|
|
*
|
|
* @param action The action to be performed for each element
|
|
*/
|
|
@Override
|
|
public void forEach(Consumer<? super E> action) {
|
|
if (action == null) {
|
|
throw new NullPointerException("action must not be null");
|
|
}
|
|
|
|
for (int i = 0; i < mSize; ++i) {
|
|
action.accept(valueAt(i));
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public Object[] toArray() {
|
|
Object[] result = new Object[mSize];
|
|
System.arraycopy(mArray, 0, result, 0, mSize);
|
|
return result;
|
|
}
|
|
|
|
@Override
|
|
public <T> T[] toArray(T[] array) {
|
|
if (array.length < mSize) {
|
|
@SuppressWarnings("unchecked") T[] newArray =
|
|
(T[]) Array.newInstance(array.getClass().getComponentType(), mSize);
|
|
array = newArray;
|
|
}
|
|
System.arraycopy(mArray, 0, array, 0, mSize);
|
|
if (array.length > mSize) {
|
|
array[mSize] = null;
|
|
}
|
|
return array;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* <p>This implementation returns false if the object is not a set, or
|
|
* if the sets have different sizes. Otherwise, for each value in this
|
|
* set, it checks to make sure the value also exists in the other set.
|
|
* If any value doesn't exist, the method returns false; otherwise, it
|
|
* returns true.
|
|
*/
|
|
@Override
|
|
public boolean equals(@Nullable Object object) {
|
|
if (this == object) {
|
|
return true;
|
|
}
|
|
if (object instanceof Set) {
|
|
Set<?> set = (Set<?>) object;
|
|
if (size() != set.size()) {
|
|
return false;
|
|
}
|
|
|
|
try {
|
|
for (int i = 0; i < mSize; i++) {
|
|
E mine = valueAt(i);
|
|
if (!set.contains(mine)) {
|
|
return false;
|
|
}
|
|
}
|
|
} catch (NullPointerException ignored) {
|
|
return false;
|
|
} catch (ClassCastException ignored) {
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
@Override
|
|
public int hashCode() {
|
|
final int[] hashes = mHashes;
|
|
int result = 0;
|
|
for (int i = 0, s = mSize; i < s; i++) {
|
|
result += hashes[i];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* <p>This implementation composes a string by iterating over its values. If
|
|
* this set contains itself as a value, the string "(this Set)"
|
|
* will appear in its place.
|
|
*/
|
|
@Override
|
|
public String toString() {
|
|
if (isEmpty()) {
|
|
return "{}";
|
|
}
|
|
|
|
StringBuilder buffer = new StringBuilder(mSize * 14);
|
|
buffer.append('{');
|
|
for (int i = 0; i < mSize; i++) {
|
|
if (i > 0) {
|
|
buffer.append(", ");
|
|
}
|
|
Object value = valueAt(i);
|
|
if (value != this) {
|
|
buffer.append(value);
|
|
} else {
|
|
buffer.append("(this Set)");
|
|
}
|
|
}
|
|
buffer.append('}');
|
|
return buffer.toString();
|
|
}
|
|
|
|
// ------------------------------------------------------------------------
|
|
// Interop with traditional Java containers. Not as efficient as using
|
|
// specialized collection APIs.
|
|
// ------------------------------------------------------------------------
|
|
|
|
private MapCollections<E, E> getCollection() {
|
|
if (mCollections == null) {
|
|
mCollections = new MapCollections<E, E>() {
|
|
@Override
|
|
protected int colGetSize() {
|
|
return mSize;
|
|
}
|
|
|
|
@Override
|
|
protected Object colGetEntry(int index, int offset) {
|
|
return mArray[index];
|
|
}
|
|
|
|
@Override
|
|
protected int colIndexOfKey(Object key) {
|
|
return indexOf(key);
|
|
}
|
|
|
|
@Override
|
|
protected int colIndexOfValue(Object value) {
|
|
return indexOf(value);
|
|
}
|
|
|
|
@Override
|
|
protected Map<E, E> colGetMap() {
|
|
throw new UnsupportedOperationException("not a map");
|
|
}
|
|
|
|
@Override
|
|
protected void colPut(E key, E value) {
|
|
add(key);
|
|
}
|
|
|
|
@Override
|
|
protected E colSetValue(int index, E value) {
|
|
throw new UnsupportedOperationException("not a map");
|
|
}
|
|
|
|
@Override
|
|
protected void colRemoveAt(int index) {
|
|
removeAt(index);
|
|
}
|
|
|
|
@Override
|
|
protected void colClear() {
|
|
clear();
|
|
}
|
|
};
|
|
}
|
|
return mCollections;
|
|
}
|
|
|
|
/**
|
|
* Return an {@link java.util.Iterator} over all values in the set.
|
|
*
|
|
* <p><b>Note:</b> this is a fairly inefficient way to access the array contents, it
|
|
* requires generating a number of temporary objects and allocates additional state
|
|
* information associated with the container that will remain for the life of the container.</p>
|
|
*/
|
|
@Override
|
|
public Iterator<E> iterator() {
|
|
return getCollection().getKeySet().iterator();
|
|
}
|
|
|
|
/**
|
|
* Determine if the array set contains all of the values in the given collection.
|
|
* @param collection The collection whose contents are to be checked against.
|
|
* @return Returns true if this array set contains a value for every entry
|
|
* in <var>collection</var>, else returns false.
|
|
*/
|
|
@Override
|
|
public boolean containsAll(Collection<?> collection) {
|
|
Iterator<?> it = collection.iterator();
|
|
while (it.hasNext()) {
|
|
if (!contains(it.next())) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Perform an {@link #add(Object)} of all values in <var>collection</var>
|
|
* @param collection The collection whose contents are to be retrieved.
|
|
*/
|
|
@Override
|
|
public boolean addAll(Collection<? extends E> collection) {
|
|
ensureCapacity(mSize + collection.size());
|
|
boolean added = false;
|
|
for (E value : collection) {
|
|
added |= add(value);
|
|
}
|
|
return added;
|
|
}
|
|
|
|
/**
|
|
* Remove all values in the array set that exist in the given collection.
|
|
* @param collection The collection whose contents are to be used to remove values.
|
|
* @return Returns true if any values were removed from the array set, else false.
|
|
*/
|
|
@Override
|
|
public boolean removeAll(Collection<?> collection) {
|
|
boolean removed = false;
|
|
for (Object value : collection) {
|
|
removed |= remove(value);
|
|
}
|
|
return removed;
|
|
}
|
|
|
|
/**
|
|
* Remove all values in the array set that do <b>not</b> exist in the given collection.
|
|
* @param collection The collection whose contents are to be used to determine which
|
|
* values to keep.
|
|
* @return Returns true if any values were removed from the array set, else false.
|
|
*/
|
|
@Override
|
|
public boolean retainAll(Collection<?> collection) {
|
|
boolean removed = false;
|
|
for (int i = mSize - 1; i >= 0; i--) {
|
|
if (!collection.contains(mArray[i])) {
|
|
removeAt(i);
|
|
removed = true;
|
|
}
|
|
}
|
|
return removed;
|
|
}
|
|
}
|